Our paper naturally consisted of two parts with the first part
providing theoretical data that we interpreted in the second part in
terms of bounds on coefficients of gravitational EFTs. In the first
part, using amplitudes methods, we obtained the one-loop
four-graviton amplitude with a minimally-coupled massive particle of spin up to \(S=2\)  circulating in the loop. By series expanding these
amplitude in large mass, we obtain theoretical data for Wilson
coefficients which we analyze in the second part. Combining this data
with similar theoretical data obtained from tree-level string-theory amplitudes
we found that the Wilson coefficients fall on small islands compared to
the general bounds coming from consistency of \(2\rightarrow 2\)  scattering determined along the lines of
Refs. [1]}, [2]}, [3]}.
It is quite striking that the EFT coefficients derived from
both string-theory and one-loop-massive amplitudes land on the
same small islands. Remarkably this can be explained as a
consequence of low-spin dominance in the partial-wave expansions.
